Rates of chronic diseases vary substantially between American Indians and Alaska Natives (AIANs) and U.S. white populations for reasons that are largely unknown. Although little is known about factors that affect chronic diseases in AIANs, incidence rates for most chronic diseases are increasing. This 4-year proposal focuses on the development of an AIAN cohort to obtain a better understanding of the disparity in disease rates and risk factor knowledge that exist between AIANs and U.S. white populations. The purpose of this proposal is to develop valid and reliable methods to obtain diet, physical activity, and lifestyle information and to determine the most efficient and effective ways to recruit, enroll, and track study participants from diverse populations. We will work with local communities to develop culturally appropriate questionnaires that will accurately capture dietary intake, physical activity patterns lifestyle and cultural habits. We will work with local health providers and the Indian Health Service to access relevant study-related data from medical records and we will establish population-based recruitment methods. Starting in year 3 of the proposal, we will initiate recruitment and data collection, testing various protocols to determine the most efficient and effective way to conduct the study. We project that 2000 Alaska Natives, 3000 American Indians from the Navajo Nation, and 1500 American Indians from the Plains states will be enrolled over a 24-month time period. This number of participants is needed to adequately test our ability to enroll large numbers of individuals as well as determine potential burden to clinics as a result of enrollment. The major scientific goal of the AIAN cohort is to determine how diet, physical activity, and other lifestyle and cultural factors relate to the development and progression of chronic diseases such as cancer, cardiovascular disease, stroke, Type 2 diabetes, chronic lung and respiratory diseases, and related mortality from these diseases. Study data will be used to assess health status and identify groups of the population at risk for various health conditions. Longitudinal data will be used to identify factors that contribute to health and prevent disease. The AIAN cohort will serve as a resource to enhance research and training activities of AIAN students interested in health research, health education, and general public health.